1. Field of the Invention
This invention relates to a video image capture device, and in particular relates to a video image capture device which performs zoom operations using an optical system having distortion characteristics.
Priority is claimed on Japanese Patent Application No. 2005-328511, filed Nov. 14, 2005, the content of which is incorporated herein by reference.
2. Description of Related Art
In image input devices such as camcorders, and digital cameras, zoom functions are widely used, in which the lens focal distance is modified so as to freely enlarge and reduce an image, corresponding to the distance to the subject for image capture and the size occupying the angle of view. Such zoom functions are broadly divided into optical zoom, which is ordinarily realized by mechanically moving an internal lens, and electronic zoom, in which a portion of the image data output from an image sensor is enlarged. Compared with the optical zoom, the electronic zoom requires no driving portions and is compact and inexpensive, but image quality suffers because a portion of the image data is enlarged.
In Japanese Unexamined Patent Application, First Publication No. 10-233950, an electronic zoom image data input method is proposed. This image data input method employs a fixed-focal distance image input optical system having a function for compressing the peripheral portion of an input image and a light-receiving element with primarily uniform pixel density which receives the light of the image. In this image data input method, zoom image data at an equivalent resolution is realized in the area of operation owing to a function for correction conversion of optically received images of the light-receiving element including distortion caused by compression. By adopting such a method, although image quality degradation in the peripheral portion cannot be avoided, image data in the center portion of the image with minimal degradation of both wide-angle image data and of telescopic image data can be obtained.
When the zoom image capture is performed using a camcorder, digital camera or similar, the position of the image for zoom capture is sought using a wide-angle image, and when the position of the image for zoom image capture is thus determined, zoom operation is performed using this position, and a zoom image of the desired subject is captured. When performing zoom image capture, moreover, the device returns to a wide-angle image to confirm the angle of view. Hence the ability to rapidly select and display a wide-angle image and a zoom image is desirable. Moreover, at the time of reproduction the ability to rapidly select and display a wide-angle image and a zoom image is desirable.